The purpose of HERS Trial was to evaluate whether hormone replacement therapy with estrogen and progesterone reduce future cardiac events in women with established coronary artery disease. The trial recruited 2,700 women at centers across the United States. The primary findings of the trial were that there was no beneficial effect hormone replacement on cardiac events over a 2-3 year period. The trial will be continued to see if there is a net benefit from hormone replacement over a longer period of follow-up.